E.ON's coal-fired Ratcliffe-on-Soar power station in Nottinghamshire. Photograph: David Sillitoe/Guardian

In the final weeks of 2010, 20 individuals – including myself – went on trial after being accused of conspiring to shut down the Ratcliffe-on-Soar coal power station. Today we received our sentences. The jury were presented with a wealth of evidence, not seeking to disprove the charge, but to justify it.

The jury received a more extensive education on climate change than most people get in a lifetime. That they could not vindicate our actions is nothing to get self-righteous about; it is deeply disturbing. If the jury, after everything they had heard, couldn't bring themselves to sympathise with our actions, who will?

I first became engaged in climate change in 2005. At the time I was filled with optimism. People appeared to be waking up to the issue in the nick of time. Like hundreds of others, we launched a community action group in our town. When we hosted a public meeting it was standing room only. A few months on we saw a Tory leader proclaiming the virtues of cycling and micro-power generation. Direct action groups such as the Camp for Climate Action saw their numbers swell from tens to hundreds, to thousands.

Yet at the start of 2009 a depressing reality emerged. Climate change may have become ingrained in public discourse, but what had been achieved?

My local group had campaigned tirelessly to reopen the town train station, promoting greener transport, only to be repeatedly told by our MP there was nothing he could do. The government had continued to advocate new coal over renewables. The impending Copenhagen climate conference was already set to result in utter failure. The financial crises saw a mass withdrawal from the issue on the part of politicians and the media. And if things couldn't get any worse, climate scepticism was re-emerging.

Two years later, climate change already appears to be an issue of the past. Our bike-loving prime minister chose to travel to the World Cup bid rather than participate in the UN climate conference in Cancún. Climate change gets a fraction of the attention it enjoyed not so long ago.

So what happened to the climate movement? What happened to the community groups, the marches, the Climate Camps? They are all still there, battling on. My local group still fights for that train station, Climate Camps still pull in thousands of participants every summer, and the marches continue.

But we never reached the critical mass required to combat the fatigue the issue now faces. Despite those packed village halls, streets, and fields of climate campaigners, there are huge swaths of society that were never engaged at all.

Will the next 12 months see climate change, the issue, continue to slide into obscurity as climate change, the reality, kills at an ever escalating rate? If we are to reverse the current trend we need to do more than lobby our MPs. We need to do more than shut down coal-fired power stations. In 2011 we need to begin a comprehensive grassroots engagement project.

This is no small task. Three weeks in front of the world's leading climate experts didn't do it for 12 people from Nottingham. This scheme requires long-term commitment. Getting out and talking about these challenging issues is draining and comes with little glory. But those of us terrified by the prospect of climate change cannot afford to ignore those who don't feel the same way.

This is not an exercise in handing out graphs and charts, but it requires us to stare hard into our communities and start joining up the dots. It's the same energy companies that cling to coal who force pensioners into deadly fuel poverty. It's the same government who fails to invest in green jobs, that cuts the UK flood defence budget. There are many avenues for making the links and connections, should we commit the effort.

The jury in Nottingham gave us a revealing litmus test, and moaning about it will do no good. We need to learn lessons, engage beyond any prescribed "target audience", and give the climate movement the renewal it so desperately needs.

• Bradley Day has been campaigning on climate issues for the past five years. He has devoted much of this time to organising the Camp for Climate Action.